Trailer Marker Lights Flicker When Tow Vehicle Is Off

Updated 05/22/2019 | Published 05/20/2019

Question:

When my landscape trailer is hooked up to my truck, and the truck is off, has been off, and they key is removed, the side lights flicker about every ten seconds. Is this normal or is there an indication of a problem.

asked by: Marina

Expert Reply:

If the side marker lights on your trailer are flicking when the tow vehicle is off then you most likely have a short on the running light wire on your trailer. This is usually a brown wire that runs from each tail light and side marker light up to the trailer connector. What I believe is happening is that this circuit is shorting out to either the trailer battery (if present) or the 12 volt circuit. Therefore, you will have no choice but to trace the running light wire back from each light up to the trailer connector to make sure there are no shorts.

The above issue could also be caused by corrosion inside either trailer connector so that is something that you will need to check as well.

expert reply by: Conner L